Method of making printing-surfaces.



No. 756,753. PATENTED APR. 5, 1904. F. G. WHIPPEY.

METHOD OF MAKING PRINTING SURFACES.

APPLICATION IILIED SEPT. a, 1903.

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Patented April 5, 1904.

UNiTnn STATES PATENT OFFICE.

FREDERICK C. WHIPPEY, OF CINCINNATI, OHIO, ASSIGNOR TO THE WHIPPEYPROCESS 8: ENGRAVING CO., OF CINCINNATI, OHIO, A

CORPORATION DELAWARE.

METHOD OF MAKING PRINTING-SURFACES.

SPECIFICATION forming part of Letters Patent No. 756,753, dated April 5,1904.

Application filed September 3,1903. Serial No. 171,753. (No specimens.)

To all whom, it may concern:

Be it known that I, FREDERICK C. VVHIPPEY, a citizen of the UnitedStates, residing at Cincinnati, Hamilton county, Ohio, have invented acertain new and useful Improvement in Methods of MakingPrinting-Surfaces, of which the following is a full, clear, and exactdescription, such as will enable others skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawing, forming part of this specification.

This invention relates to a new and useful improvement in the method ofmaking printing-surfaces for the purpose of reproducing drawings orphotographs and the like, the object being to simplify the reproductionof drawings or photographs by surface impressions from printing-presseson a larger scale than has heretofore been possible with the method ofhalf-tone reproductions generally practiced.

With this object in view the invention consists in the methodhereinafter described and afterward pointed out in the claims.

In order that my invention may be understood, I will describe brieflythe method at present in vogue in reproducing photographs or drawings bythe half-tone process. The picture to be reproduced is photographed ontoa sensitized plate arranged behind a grained, stippled, or lined screenwhose opaque portions are located at varying distances apart, dependingupon the character of the work to be done and the type ofprinting-presses on which it will be used. After this screennegative, asit might be called, is exposed it is developed and transferred onto theprinting-plate, as is well known. The size of the resultant half-tone isdetermined by the size of the screen-negative, and these limitationscannot be varied by any known process of which I am awarefias thescreen-negative is .Durlng the transferring of the screen-negative ontothe printing-plate special apparatus is required involving the use ofextremely thick glass capable of withstanding considerable pressureduring the transferring process, and this alone imposes limitations onthe size of the printing-plate which cannot conveniently be varied from.The method pursued in halftone reproduction is well known to thoseskilled in the art, and I will not go into a detailed description of thesame here, asI deem it unnecessary, except in so far as I employ certainsteps of the old method in practicing the new in the production ofenlarged printing-surfaces.

I will now describe my improved method: For purposes of illustration Iwill assume that the picture to be reproduced is an ordinaryphotographsay, for instance, a portrait of cabinet sizeto wit, fourinches by five inchesalthough it is obvious that line-drawings,wash-drawings, crayons, pastels, or other pictures may be treated in thesame way. The first step is to obtain a negative, andto do this in thecase of a photograph I follow the practice well known in ordinaryhalf-tone work" that is, the plate is placed behind the screens and anexposure made so as to obtain the negative. In the instance of apen-and-ink drawing no screen need be used. This negative is developedin the usual way and dried. After the negative is made I follow thesteps usual in enlarging pictures that is, I prefer to have a constantsource of light, which may be rays of light from the sun, but preferablyan electric-arc light, where the upper and lower carbons are-fed tomaintain the are in one position for some considerable length of. time.The rays oflight, from whatever source, are preferably passed throughcondensing-lenses and through the screen-negative, the image beingreceived upon the lens of the camera and transmitted and enlarged uponthe transferring-surface.

In the accompanying drawing I have shown such an apparatus, in which 1is the source of light. 2 represents the condensing-lenses, arranged inan opening in adark room. 3 is the screen-plate; 4, the camera-bellows;5, the lensholder of the camera, and 6 the transferringsurface upon asuitable plate or support 7 This transferring-surface is a sensitizedemulsion painted or spread in a thincoat upon a plate of copper, zinc,aluminium, stone, &c. A proper time is allowed for the exposure, theapparatus-of course being adjusted so as to bring the image in sharpdefinition upon the sensi-' tized transferring-surface, and after theexposure is made the following steps aretaken: If the zinc,copper,aluminium, stone,&c. plate is to form a printing-surface from whichimpressions are to be made, as in half-tone reproductions, the entiresurface of the sensitized emulsion is preferably coated with ink. Theplate is now developed or washed, the Water or developing fluiddissolving or acting upon and removing the unexposed portions of thetransferring-surface, leaving the portions which were exposed and actedupon by the actinic rays. The backing-plate 7 is now immersed in an acidor other suitable bath for the purpose of etching the same, after whichthe plate may be Washed off to remove all of the emulsion, whereby thesurface of the plate may be printed from or the emulsion may be left onthe plate and the printing impression made from the surface of theemulsion.

I have referred tothe exposed and unexposed portions of the sensitizedtransferringsurface 6, and with respect to this I will say that thescreen-negative, which is usually a negative composed of opaque dots andsquares whose sizes are determined by the number of lines per inch inthe screen, they ranging from fifty lines per inch to four hundred andover, will permit the passage of actinic rays only through thetransparent portions of the negative, and these in every case alternatewith the opaque portions. Thus it will be seen that thetransferringrsurface 6 is not entirely exposed, as is the case in makingordinary bromid enlargements; but only portions thereof are exposedwhich render it possible to bring out the image with distinctness anddefinition usually absent from bromid enlargements. In other words,because of the separation of the transparent spaces the deep shadows andhigh lights are in greater contrast, which. contributes materially tothe clearness of the resultant prints' The sensitizedtransferring-surface 6 after being treated with a coating of ink andwashed, as before described, may be dipped into an acid-bath for thepurpose of subjecting the exposed surface of the plate 7 to the etchingaction of the acids, and the remaining emulsion may be washed off andthe printing impressions made direct from the plate 7, or the emulsionmay be left on and the printing made from the emulsion. I do not wish tobe limited in the practice of my process to either of these, nor, infact, to the coating of the ink on the emulsion previous to washingferent manner where it is desired to reproduce a picture by thelithographic process instead of from direct impressions from thebackingplate. This is well known to lithographers;

' but in order that the practice may be understood I will brieflydescribe it here. Assuming that the transferring-surface 6 is inked andWashed, as before described, it will be necessary to transfer theexposed portions of the plate to stone or other suitable material forlithographing purposes. This is done by first coating the exposedsurface with gum-arabic and water, after which the protective coating ofink on the exposed surfaces is Washed off, usually by the use ofturpentine. The transferring lithographing-ink is now coated over theentire surface, so as to cover the exposed as well as the unexposedsurfaces of the plate. Water is now employed to again wash the plate andacting upon the gum-arabic will remove all ink from-the unexposedportions of the plate,

leaving the transferring-ink on the exposed portions which were formerlycovered by the protective ink. A sheet of transfer-paper is now placedover the plate to take an impression, said sheet of paper receiving thetransferring-ink which is only on the exposed parts of the plate. Thissheet of paper is removed and placed on a lithographing-stone and animpression made therefrom, which deposits the transferring-ink on thestone at such points as were exposed on the original transferringsurface6. The stone is now treated in the usual way by subjecting its exposedsurface to acids, which etch the stone and leave the transferring-ink toform the projections which.

ferent colors possess different characteristics,.

and a negative is made for the three primary colors' to Wit, red, blueand yellow. The three-color negatives may be enlarged on the sensitizedtransferring-surface 6, and these surfaces may be employed, as is wellunderstood, in the printing ofhalf-tone reproductions in colors, they ofcourse necessitating three different impressions, with appropriatecolors, to thus produce the desired result.

This application is a continuation of a prior application, Serial No.62,603, filed by me on or about May 31, 1901.

I am aware that there are operations in the arts of half-tonereproductions, enlargements, and lithography which might be employed toadvantage in connection with my improved method; but I have not deemedit necessary here to give a detailed description of those variousoperations and auxiliaries, as they might be called, as they willreadily suggest themselves to those skilled in those arts.

Having thus described the invention, what is claimed as new, and desiredto be secured by Letters Patent, is

1. The herein-described method of making printing-surfaces consisting infirst making a negative with alternating opaque and transparentportions, transmitting rays of light through such negative and afocusing-lens onto a transferring-surface made up of sensitizedemulsion, whereby the actinic rays act only upon a portion of suchtransferring-surface,

then dissolving the remaining portion of such transferring surface;substantially as described.

2. The method of making printing-surfaces consisting in first making anegative composed of alternate transparent and opaque portions,condensing rays of light onto and through said negative and through aphotographic lens onto a sensitized transferring-surface, wherebyalternate portions of such transferringsurface are exposed andunexposed, dissolving the unexposed portions of the transferringsurface,and finally treating the backing-plate on which the sensitizedtransferring-surface is coated to an acid-bath for the purpose ofetching said backing-plate throughout the unexposed portions of thetransferring-surface; substantially as described.

In testimony whereof I hereunto aflix my signature, in the presence oftwo Witnesses, this 31st day of August, 1903.

FREDERICK (J. WHIPPEY.

Witnesses:

F. R. CORNWALL, GEORGE BAKEWELL.

